Convertible ski-supported vehicle

ABSTRACT

Wheel unit on the ski of a snowmobile. Wheels are readily deployable or retractable as ground surface conditions require. The wheel unit allows the snowmobile to be driven over gravel, dirt, and hardtop surfaces, while maintaining steerability with the handlebars. The wheel unit is a separate assembly that is detachably mountable on the ski or is an integral component of the ski.

[0001] This application is a Continuation-in-Part (CIP) of U.S. patent application Ser. No. 09/818,058, filed on Mar. 26, 2001.

BACKGROUND INFORMATION

[0002] 1. Field of the Invention

[0003] The invention relates to the field of ski-supported vehicles. More particularly, the invention relates to snowmobiles equipped with wheels that will allow the snowmobile to travel readily over surfaces not covered with snow or ice.

[0004] 2. Description of the Prior Art

[0005] Snowmobiles are vehicles that are constructed to travel across snow and ice. As is generally known, the snowmobile is driven by an endless drive track arranged at the rear end of the underside of the snowmobile. The front end of the snowmobile is supported and rides along two skis, which glide across the surface of the snow or ice. The skis typically have a carbide runner that runs along a portion of the bottom surface of the ski, to help keep the snowmobile traveling along a smooth track.

[0006] A disadvantage of snowmobiles is that the skis don't readily glide across gravel, hardtop, or other non-snow surfaces. This makes it difficult, if not impossible, to steer a snowmobile because the skis do not respond properly to the steering operations initiated at the handlebars. Quite often, the snowmobile needs to be dragged or pushed in driveways and across roadways, etc. Furthermore, when a snowmobile is driven or dragged across a non-snow surface, the carbide runners on the skis are subject to excessive wear and must be replaced more frequently, depending on how often a snowmobile travels across a non-snow surface. This inability to steer snowmobiles on surfaces other than snow and ice makes it difficult for people to maneuver their snowmobiles across roadways, driveways, onto ferries, etc.

[0007] In recent years, the sport of snowmobiling has changed evolved from one of traveling relatively short distances over trails close to home to one of weekend-long or longer cross-country trips. Previously, for example, a snowmobile operator would fill the gasoline tank of the snowmobile in his or her backyard, transport the snowmobile to a trail site or depart directly from the backyard for an afternoon or day of travel over snowmobile club trails, and then return home. Nowadays, people are traveling great distances across country on snowmobiles that involve two- or three-day tours or even such mammoth tours as from Alaska to Maine.

[0008] This development of the sport of snowmobiling into extended trips means that snowmobiles must now be refilled with gasoline and maintained while they are out traveling across open country. Thus, where in the past the tank on the snowmobile was filled at home or at the point of departure before a daylong excursion, snowmobiles now need to be refilled while out traveling. This means that the snowmobile must be driven to a service station, typically by traveling some distance along a road surface other than snow or ice. Also, now that such lengthy trips are being undertaken with snowmobiles, the presence of snow along the entire route is not guaranteed, and consequently, snowmobiles are being required more and more frequently to travel some distance across surfaces other than snow or ice. Before, when a snowmobile needed to be dragged or pushed only a short distance across a roadway or driveway, or up a ramp onto a ferry, it was possible for a person to do it alone or with the assistance of a traveling companion. Now, however, with the need to travel several miles along a roadway to get to a filling station, the inability to steer a snowmobile has become a major obstacle in the logistics and the enjoyment of the sport.

[0009] Efforts to make snowmobiles mobile on gravel or other surfaces have been undertaken over the years. Prior art includes conversion kits to replace the skis with wheels. These conversion kits were intended to replace the skis on a semi-permanent basis, that is, to convert a snowmobile into a wheeled vehicle for an extended period of time. Such conversion kits typically require that the ski be removed in order to mount the wheels, or, if the ski does remain attached to the vehicle, a longer kingpin must be used to mount the wheels. Thus, each time the wheels are mounted or removed, the kingpin must be replaced with the longer or shorter one, respectively. Both methods of converting the snowmobile to a wheeled vehicle involve a fair amount of work. Thus, such conversion kits are not generally an acceptable solution to the problem of having to change in relatively quick succession back and forth between a vehicle that rides on skis and one that rides on wheels, as happens when traveling over gravel or hardtop or other surface other than snow or ice to fill the gas tank or to load onto a ferry.

[0010] What is needed, therefore, is a means for quickly converting a vehicle from one gliding on skis to one rolling on wheels and back. What is further needed is such a means that will not impair the steerability of the vehicle. What is yet further needed is such a means that can be implemented easily, without requiring great physical strength, and without requiring the use of tools.

SUMMARY OF THE INVENTION

[0011] An object of the present invention is to provide a combination ski-wheel unit that will allow one to convert a ski-supported vehicle quickly and easily to a wheeled vehicle and back to a ski-supported vehicle, without requiring the use of tools. Another object of the present invention is to provide such a unit that will maintain the steerability of the vehicle, whether on skis or on wheels. A further object is to provide such a unit that, once installed, can be easily deployed without requiring great physical strength. Still another object is to provide a wheel kit with deployable wheels that can be retrofitted onto any conventional snowmobile ski.

[0012] The objects are achieved by providing a road wheel unit that is semi-permanently installed on the ski of a conventional snowmobile so as to provide a set of wheels that are easily deployable or retractable as the conditions require. In a retracted position, i.e. the standard snowmobile mode of operation, the wheels are carried alongside the ski, raised above the gliding surface of the ski. In a deployed position, the wheels are lowered, so that the weight of the machine is supported by the wheels. The wheels in this deployed position hold the ski above the rolling surface of the wheels, and allow the snowmobile to ride on wheels and the conventional endless track at the rear end. In the latter mode, the snowmobile remains readily steerable with the handlebars and the carbide runners on the ski surfaces are not subject to excessive wear. The wheels are easily detachable from the mounting means, leaving the mounting means permanently installed on the vehicle, without impairing the functionality of the skis.

[0013] The scope of the invention includes a wheel unit that is mountable on the kingpin that links the ski to the snowmobile, as well as a wheel unit that is mountable on the side wall of the ski or mountable onto a mounting block that is integrated into the side wall construction of the ski. The wheel unit mountable on the kingpin is hereinafter referred to as the kingpin-mount wheel unit; the unit mountable on the side wall or onto a mounting block integrated into the side wall construction is hereinafter referred to as the side wall-mount wheel unit. A manually actuatable or power-assisted deployment means is suitable for both types of wheel unit. A manually actuatable deployment means includes essentially a side rail connected to which a wheel-mounting bracket with a cam end is attached. The wheel is mounted at the cam end of the bracket so that it is eccentrically mounted relative to the wheel-deployment means. Moving the side rail causes the cam end to swing about the connecting point between wheel-mounting bracket and wheel-deployment means, thereby bringing the wheel into a deployed or a retracted position, respectively.

[0014] The kingpin-mount wheel unit includes a kingpin to replace the conventional kingpin to which the ski spindle attaches, a wheel mounting bracket mounted on each side of the kingpin. The deployment means is mounted onto the wheel mounting bracket, outside the ski. In the case in which a pair of wheels is mounted on one ski, i.e., one wheel on each outer side of the ski, a crossbar is used to connect ends of each of the side rails to form a movable frame. In this way, grasping the crossbar and moving the frame results in the cams on both wheel units being moved simultaneously.

[0015] A locking mechanism is provided in the ski to ensure that the side rail is locked into the respective deployed-wheel or retracted-wheel position. In a simple locking mechanism used on the kingpin-mount wheel unit, a yoke depends from the crossbar into the inner contour of the ski. The bottom portion of the yoke latches into the latching mechanism that is mounted on the floor of the ski. To deploy the kingpin-mount wheel unit, a person lifts the ski by the handle that is typically provided at the front end of the ski, grabs hold of the crossbar and slightly lifts and slides it forward toward the front end of the ski until the yoke latches in the latching mechanism. The two wheels, one on each side of the ski, are thereby lowered and secured in the deployed position. The snowmobile can now be driven across gravel and hardtop surfaces without losing its ability to be steered with the handlebars.

[0016] To retract the wheels, the procedure is reversed. A person lifts the ski until the weight of the snowmobile is off the wheels, grabs the crossbar and slides it toward the rear end of the ski until it is secured in a retracted position. The wheels are now secured in a raised or retracted position in which the lowest point of the wheels is above the gliding surface of the ski, allowing the snowmobile to glide fully on the skis.

[0017] In some cases, it is desirable to mount the wheel unit on the side wall of the ski, rather than on a kingpin. The side wall-mount wheel unit is provided for this purpose. A mounting plate is mountable on the side wall and the wheel-mounting bracket is mounted on a spindle that extends from the mounting plate. As with the kingpin-mount wheel unit, either one wheel or a pair of wheels is mounted on each ski. Again, if a pair of wheels is mounted on the ski, a crossbar links the distal ends of the side rails, so that moving the crossbar causes both side rails to move simultaneously, thereby ensuring that the wheels are deployed/retracted simultaneously.

[0018] It is within the scope of this invention to also provide a wheel unit for ski-mounted vehicles that is automatically actuatable. The deployment means described above involves a simple mechanical actuation. Any number of known automated or power-assisted means of actuating a cam mechanism is suitable for deploying and retracting the wheels. In one embodiment, the movable frame is spring-biased toward the retracted position, so that, when the snowmobile weight is lifted from the ski, the spring-biased movable frame snaps back to a “retracted” position, thereby causing the wheels to automatically spring back to the retracted position. Other means for actuating the deployment means according to the invention include such means as a pivot arm or linkage driven by an electric motor, an electromagnetic means in which magnets are selectively magnetized to draw the frame to a deployed or retracted position, or hydraulic or pneumatic means. A small electric motor is mountable within the inner contour of the ski, for example, and then wired to a thumb switch on the handlebar of the snowmobile. The motor drives a shaft that is connected to an arm that is pivotably linked to the frame. When the shaft extends, the frame is pushed to a deployed position, thereby lowering the wheels to an operable level, and when the shaft retracts, it pulls the frame to a retracted position, thereby lifting the wheels above the level of the gliding surface of the ski. An indicator, for example, a warning light, is arranged on the dashboard or on the handlebar, to alert the operator when the wheel unit is deployed.

[0019] Although it is desirable that snowmobiles be sold already equipped with skis having a wheel unit according to the present invention, a wheel kit is provided to retrofit a ski for any number of the conventional snowmobiles already available. The ski itself need not be modified. When retrofitting to receive the kingpin-mount wheel unit, the original kingpin may need to be replaced with a longer kingpin, to which the kingpin-mount wheel unit is then attached. When retrofitting a ski that does not have a suitable kingpin mounting assembly, or if a side-wall mounting is desired for other reasons, the mounting plate of the side wall-mount wheel unit is fastened to the side wall of the ski and the wheel deployment means and wheel assembly are then mounted on the plate. Depending on the type of wheel unit actuation means chosen, manual, electric, or other, an actuation means, a switch and/or an indicator light are retrofittable retrofitted on the dash of the snowmobile.

[0020] With the wheel unit of the present invention, the wheels are semi-permanently mounted on the ski. Depending on the particular travel conditions, the wheels are deployed, so that the snowmobile becomes a wheeled vehicle, or retracted, so that the wheels are carried along side the ski in a raised position, above the gliding surface of the ski.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021]FIG. 1 shows a perspective view of a conventional snowmobile ski (prior art).

[0022]FIG. 2 is a perspective view of a portion of a ski, showing a first embodiment of the kingpin-mounted wheel unit according to the invention, and the deployment means.

[0023]FIG. 3 is a perspective view of a ski according to the invention, showing the wheel unit of FIG. 2 in a retracted position, with the movable frame and a latching mechanism.

[0024]FIG. 4 shows a spring-biased movable frame according to the invention.

[0025]FIG. 5 shows a cross-section of the wheel unit of FIG. 2, showing the movable frame within the ski profile and a motor.

[0026]FIG. 6 shows in detail the wheel mount on the modified kingpin according to the invention.

[0027]FIG. 7 is a perspective view of a motorized wheel unit according to the invention.

[0028]FIG. 8 is a partial view of a dashboard of a snowmobile, illustrating the thumb switch to actuate the wheel unit according to the invention, and an indicator light to indicate that the wheels are deployed.

[0029]FIG. 9 shows a second embodiment of the kingpin-mounted wheel unit according to the invention.

[0030]FIG. 10 is a side view of the deployment means of the wheel unit of FIG. 9, showing the side rail and the wheel-mounting bracket.

[0031]FIG. 11 is a cross-sectional view of the wheel unit of FIG. 9, showing the connections between the wheel-mounting bracket, the side rail, and the kingpin.

[0032]FIG. 12 is a perspective view of an alternative embodiment of the wheel unit according to the invention, showing a side-wall-mounted wheel unit mounted on a double-scag type ski.

[0033]FIG. 13 is a side view of the side-wall mounting bracket, seated over the fasteners for fastening carbides to the double-scag type ski, and also showing the latching pin and the side-wall mounting holes for mounting the wheel unit directly to the side wall of the ski.

[0034]FIG. 14 is an end view of the double-scag type ski, showing the side-wall mountable wheel unit mounted on the side wall of the ski.

[0035]FIG. 15 is an end view of a ski, showing the side-wall mountable wheel unit mounted on the side wall of the ski.

[0036]FIG. 16 is an end view of a ski, showing a mounting block for mounting the wheel unit according to the invention integrated into the form of the ski.

[0037]FIG. 17 is an illustration of a side-wall mountable wheel unit according to the invention, with a schematically illustrated automated actuating means mounted on the side-wall mounting bar and connected to the actuating end of the side rail.

[0038]FIG. 18 is an illustration of a biasing spring as the automated actuating means of FIG. 17.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0039]FIG. 1 shows a conventional snowmobile ski comprising a ski 1 having ski sides 2, a lifting handle 3 disposed at a front end 1A of the ski, and a reinforcing liner 6. A kingpin 5 is mounted in the ski 1. With the particular ski shown, a spindle (not shown) mounts on the kingpin 5 to attach the ski 1 to the snowmobile. The present invention is a wheel unit that is mountable on the ski 1, and is either directly mountable on the kingpin 5 or on a side 2 of the ski 1. It is noted here that a reference designation assigned to a particular element of the invention is maintained hereinafter throughout the description, even if the element is used in more than one embodiment of the invention.

[0040]FIG. 2 shows a first embodiment of a kingpin-mounted wheel unit 20 according to the invention that has been assembled on the ski 1. As shown in this FIG. 2, the wheel unit 20 is in a deployed position. The wheel unit 20 comprises a deployment means that is a movable frame 12 with a cross-bar 13, a yoke 14, a modified kingpin 5A, a wheel mounting bracket 21, and a pair of wheels 18. Mounted in the bottom of the ski I is a latching means 15. In this first embodiment, the latching means 15 comprises a simple latch 16 and a stop plate 17. The movable frame 12 has been moved to a deployed position and the yoke 14 is held by the latch 16.

[0041]FIG. 3 shows the first embodiment of the wheel unit 20 in a retracted position. As can be seen, the movable frame 12 has been shifted toward a rear end 1B of the ski 1 and the yoke 14 is held in position by the stop plate 17. This embodiment is a basic mechanical embodiment of the wheel unit 20 that can be deployed manually by a snowmobile operator. To deploy the wheel unit 20 from the retracted position shown in FIG. 3, the snowmobile operator merely lifts up on the ski handle 3 with one hand, grabs the crossbar 13 with the other hand and pushes it toward a front end 1A of the ski 20 until the yoke 14 catches under the latch 16 on the latching means 15.

[0042]FIG. 5 shows a cross-section of the ski 1 with the wheel unit 20, looking from the rear toward the front of the ski 1. The movable frame 12 is mounted on the ends of a modified kingpin 5A that extend to the outer side of the sides 2 of the ski 1. The kingpin 5A is longer than the conventional kingpin 5 to allow the movable frame to be mounted on each of the kingpin 5A on the outside of each of the ski sides 2. A cam or wheel-mounting bracket 21 is attached to each end of the kingpin 5A. Mounted eccentrically on each wheel-mounting bracket 21 is a wheel mount spindle 19 for mounting the pair of wheels 18. Due to the eccentricity of the mount, the wheels 18 are in a deployed position when the frame 12 is moved into the deployed position toward the front end 1A of the ski 1 and are in a retracted position when the frame 12 is moved toward the rear end 1 B of the ski 1. As shown in FIG. 3, the yoke 14 is positioned behind the stop plate 17, with reference to the front end of the ski 1, and the wheel unit 20 is in a retracted position. As can be seen, the lowest point of each wheel 18 is raised above the gliding surface G of the ski 1.

[0043]FIG. 6 shows in greater detail the wheel cam or wheel-mounting bracket 21 and the movable frame 12 according to the invention. The wheel-mounting bracket 21 is rigidly and fixedly attached to a boss at each end of the kingpin 5A. Extending eccentrically from the cam or wheel-mounting bracket 21 is a wheel mount spindle 19. The wheels 18 are attached by means of a bolt (not shown) to each side of the ski 1 that is threaded into a threaded hole 22A in the spindle 19. The movable frame 12 is pivotably attached to the wheel-mounting bracket 21 as shown.

[0044]FIG. 4 shows a spring-biased embodiment of the wheel unit 20, comprising a biasing spring 31. In this embodiment, the wheels are placed in the deployed position manually, as described above; they are moved to the retracted position simply by lifting the weight of the snowmobile from the wheels. When the weight is lifted from the wheels, the spring-biased yoke 14 is automatically pulled to the retracted position.

[0045] A motorized wheel unit 20A according to the invention is shown in FIG. 7. The components of the motorized wheel unit 20A that are identical to those of the wheel unit 20 have the same reference designation. Mounted on the bottom of the ski 1 is an electric motor M. The wiring for the motor is not shown herein, as it is well known in the art to connect electrical devices in vehicles. A shaft S is fixedly connected at one end to the motor M and pivotably linked at the other end to a first end 13B of a pivot arm 13A. A second end 13C of the pivot arm 13A is pivotably linked to the crossbar 13 of the frame 12. When an actuation means 43 for the motor M is actuated, the shaft S is moved forward toward the front end 1A of the ski 1, causing the second end 13C of the pivot arm 13A to swing slightly up and in the direction toward the rear end 1B of the ski 1. Actuating the actuation means 43 while the shaft S is in an extended position will cause the motor to retract the shaft S, thereby causing the frame 12 to move forward to a deployed position. The description of this motor, shaft, and pivot arm is merely illustrative. Means of moving a rigid body back and forth are well known, and it is intended that the scope of this invention not be limited to a specific linkage or actuating means.

[0046]FIG. 8 shows a dashboard 40 of a snowmobile. The actuation means 43 for the motor M, which can be a thumb switch, a toggle switch, a button switch, for example, is shown mounted on the handlebars 41 of the snowmobile. An indicator light 42, shown here as mounted on the dashboard 40, indicates a deployed condition of the wheel unit.

[0047] FIGS. 9, and 9A, 10 show a second embodiment of the kingpin-mountable wheel unit 200, mounted on the kingpin 5 of the ski 1. This second embodiment is very similar to the first embodiment with regard to the way the wheels 18 are mounted eccentrically on the cam or wheel-mounting bracket 21 on the ski 1, but has a modified deployment means 212 that includes two side rails 221, an anchor bar 222, and a crossbar 213 that is connected to an actuating end 221A of each of the respective side rails 221. FIG. 9 is a perspective view of the wheel unit 200 and FIG. 9A is a cross-sectional view of the ski 1 that shows the anchor bar 222 in greater detail. The anchor bar 222 is fixedly mounted on the ski 1 forward of the kingpin 5 and has a locking pin 225 that extends from each end of the anchor bar 222 outwardly from the respective side 2 of the ski 1. Although the anchor bar 222 can be mounted by any conventional means to the ski 1, it is practical with skis that have a carbide runner 111 attached to the bottom of the ski 1 to provide a through-bore in the anchor bar 222 and to use a fastener 111A as shown for attaching both the carbide runner 111 and the anchor bar 222 to the ski 1.

[0048] See FIG. 10 for a side view of a portion of the ski 1, showing the side wall 2, the wheel 18, and the side rail 221. A curved groove 223 for receiving the locking pin 225 is provided in each side rail 221. The curved groove 223 has a first end 223A for latching the deployment means 212 in a deployed position in which the wheels 18 are in contact with the ground surface G and a second end 223B for latching in a retracted position in which the wheels 18 are raised above the ground surface G. In the embodiment shown, the mechanism by which the deployment means 212 is latched into the deployed or retracted position is very simple: the latching pin 225, once moved into the second end 223B, for example, does not release from this position until the crossbar 213 is lifted moved, thereby allowing the latching pin 225 to drop out of the latched position and move into the groove 223, along which it slides until it latches into the first end 223A. FIG. 11 is a side view of the side rail 221 and the wheel-mounting bracket 19. The crossbar 213 and the wheel 18 are shown in dotted lines only.

[0049]FIG. 12 is an illustration of an alternative embodiment of the wheel unit according to the invention. A side-wall-mountable wheel unit 300 is mountable on the outside of the ski, rather than on the kingpin 5, and comprises a side-wall mounting bracket 304, the side rail 212 previously shown in FIG. 9, the wheel-mounting bracket 21, the wheel-mounting spindle 21, and a latching pin 301. The alternative embodiment of the wheel unit according to the invention is particularly advantageous for use with the conventional double-scag ski 100 as shown in FIG. 12, or with skis without a suitable kingpin mounting. With the double-scag type ski 100, carbides are mounted on the runner surface of the ski 100 and are removably attached by means of threaded fasteners 110, such as bolts, as shown in FIG. 12. The double-scag ski 100 has contoured side walls 302 with carbide-fastener posts 303 integrated into the side wall construction. The carbide-fastener posts 303 have a bore for receiving the threaded fastener 110 that fastens the carbides to the runner of the ski 100. The side-wall mounting bracket 304 seats against the contour of the side wall 302 and is seated over the respective carbide fastener posts 303. The conventional threaded fastener 110 that is provided with the ski 100 to fasten the carbide is replaceable with a longer threaded fastener, if necessary, and is used to fasten the side-wall mounting bracket 304 as well as the carbide to the ski 100.

[0050]FIG. 13 is a side view of the side-wall mounting bracket 304 mounted on the side wall 302 of the ski 100. As seen, the side-wall mounting bracket 304 has a first mounting end 304A and a second mounting end 304B. Each of the mounting ends 304A/304B fits over a respective carbide-fastener post 303A/303B that extends upward from the side wall 302., fitted against the side wall 302 of the ski 100, showing the through-bores 110A in the carbide-fastener post 303A/B in dotted lines. These through-bores 110A serve simultaneously for attaching the side-wall mounting bracket 304 to the side wall 302. Additional mounting holes 307 for attaching the bracket 304 directly to the side wall 302 are also shown, as is a latching pin 306, one end of which is fixedly mounted on the side-wall mounting bracket 304 and the other end of which is captured in the curved groove 223 on the side rail 221 when the wheel unit 300 is assembled. The side-wall mountable wheel unit 300 is also mountable on a ski that does not provide the threaded fasteners 110. In such a case, the side-wall mounting bracket 304 is attached to the outer side wall 302 by means of suitable fasteners that are inserted through the mounting holes 307 and into bores in the side-wall 302. A deployment means 312 for this alternative embodiment of the wheel unit 300 is similar to that described above and uses the same side rail 212. The latching pin 306 that extends from the side-wall mounting bracket 304 is captured in the curved groove 223 provided in the side rail 221.

[0051]FIG. 14 is an end view of the double-scag type ski 100, showing the completely assembled wheel unit 300 fitted against the contoured side wall 302 of the ski 100 and mounted to the side wall by means of the carbide fastener 110. In this particular view, the wheel 18 is retracted.

[0052]FIG. 15 is an end view of the double-scag type ski 100, showing the side-wall mounting bracket 304 seated against the contour of the side wall 302 and attached to the side wall 302 by means of threaded fasteners through mounting holes 307. This is an example of the versatility of the alternative embodiment of the wheel unit 300, which is mountable on the double-scag type ski 100 by means of the fasteners that are inserted and fastened in the through-bores 110A, or mountable directly onto the side wall 302 of the any ski that has a side wall by means of fasteners that are inserted and fastened in the mounting holes 307. Typically, threaded fasteners are used when mounting the wheel unit 300 according to the invention, although it is included with the scope of the invention that any suitable fastener be used to mount the wheel unit 300 to the ski 100.

[0053] The side-wall mounted wheel unit 300 is preferably mounted on the ski in the area of the kingpin mounting, as shown in FIGS. 12 and 13, because the section of ski where the kingpin is mounted is the balance point of the ski. The side-wall mounting bracket 304 shown in the illustrations is one that is adapted to seat over the carbide fastener posts 303. It should be understood that a side-wall mounting bracket for mounting the wheel unit on a ski that does not have the carbide fastener posts in the side walls may have a simpler construction that allows it to be mounted against the side-wall. In other words, it is not necessary that the side-wall mounting plate have mounting ends that seat over carbide fastener posts.

[0054] A further advantage of the side-wall-mountable wheel unit 300 as shown in FIGS. 1-15 is that it is semi-permanently attachable to the particular ski. In other words, if so desired, it can be detached from the ski without impairing the ski. This is done simply by removing threaded fasteners, removing the complete wheel unit 300, and, if the wheel unit had been attached with the carbide fasteners 110 in the through-bores 110A, refastening the carbides.

[0055] The embodiments of the wheel unit according to the invention shown thus far have been separate wheel units that are mountable on conventional skis. The scope of the invention also encompasses a ski that has a wheel unit integrated into its construction. FIG. 16 is an illustration of a ski 500 which has a mounting block 503 for receiving a wheel assembly with deployment means. The mounting block 503 is molded into the side wall 502 of the ski 500. A wheel unit 600, comprising essentially the deployment means 312 with at least one side rail 221 and a latching mechanism, the cammed wheel-mounting bracket 19, and a wheel 18, is mounted on the mounting block 503. The wheel unit 600 is detachably mountable to the mounting block 503 by means of a threaded fastener or other suitable fastening means. In another embodiment, the wheel unit 600 is permanently mounted on the mounting block 503 of the ski 500.

[0056]FIGS. 17 and 18 illustrate an actuating means 38 that is rigidly mounted on a ski 400 on the side-wall mounting bar 304 and connected to the actuating end 221A of the side rail 221 by means of an actuating link 39. Suitable conventional actuating means 38 for driving the wheel-deployment means 212 of the kingpin-mountable wheel unit 200 or the side-wall mountable wheel units 300 include an electric motor with linkage to the side rail 221, a piston-and-cylinder assembly that is connected to a pressurized fluid system, such as an hydraulic system or a pneumatic system, or a biasing spring. FIG. 18 illustrates a possible mounting of a biasing spring 49 on a post 48, such that, when the ski 400 is lifted off the ground, the biasing spring 49 will urge the side rail 221 toward a retracted-wheel position. Any number of conventional actuating means are suitable for driving the wheel-deployment means of the wheel unit of the present invention and the description of an electric motor with linkage, a biasing spring mechanism, or a pressurized-fluid system with piston and cylinder is not intended to limit the actuating means to these particular embodiments or configurations. Furthermore, the power source for driving the actuating means is a conventional power source that is provided on the snowmobile and connected to the actuating means by conventional methods. For example, if the actuating means is a pneumatic system, the pressurized air tank is mountable in any convenient and suitable location on the snowmobile and connectable to the cylinder by means of a pressurized hose. It is also known to mount an actuating switch in a convenient location on the snowmobile, for example, on the dash, and to connect it to the actuating means by conventional means, such as an electric signal, an electro-magnetic relay, an infra-red signal, etc.

[0057] In many of the illustrations, the particular ski is shown with the side-wall mounted wheel unit 300 mounted on only one side of the ski. It should be understood that the invention also encompasses mounting a wheel unit 300 on each side of the ski. In such a case, it may be desirable to modify the deployment means 312 by providing a crossbar that gangs the two ends of the side rails 221 together, similar to the crossbar 213 shown above on deployment means 212, so that the wheels 18 are simultaneously deployed or retracted when the crossbar is moved.

[0058] Although the invention has been described by reference to several embodiments mentioned herein, these embodiments are merely illustrative of the present invention. It should be understood that numerous variations in construction of the present invention may be contemplated in view of the following claims, without straying from the intended scope and field of the invention herein disclosed. 

What is claimed is:
 1. A wheel unit mountable on a ski of a ski-mounted vehicle, said ski having a gliding surface for traveling over a ground surface and two side walls, a first side wall and a second side wall, that extend upward from said gliding surface and lengthwise along at least a portion of said ski, and kingpin mounting holes, one in each of said side walls for receiving a kingpin that is used to link said ski with said ski-mounted vehicle, said wheel unit comprising: a kingpin mountable in said kingpin-mounting holes, said kingpin having a kingpin-end that extends through a respective one of said kingpin-mounting holes to an outside of said first side wall; a wheel-deployment means having a side rail, a latching mechanism, and a wheel-deployment actuating means; and a wheel assembly that includes an eccentrically mounted wheel, wherein said wheel assembly is rotatably mountable on said kingpin end and shiftably linked to said side rail.
 2. The wheel unit according to claim 1, wherein said wheel assembly comprises a wheel mounting bracket that includes a cam with a wheel-mounting spindle for rotatably mounting said wheel on said bracket, a spindle mount for rotatably mounting said bracket to said kingpin end, and a deployment link that shiftably links said wheel-mounting bracket to said side rail.
 3. The wheel unit of claim 2, wherein said latching mechanism includes an anchor, a locking pin having a first pin end and a second pin end, and a curved groove in said side rail, said curved groove having a first latching position and a second latching position; and wherein said locking pin is fixedly attached to said anchor by said first pin end and is slidably captured at said second pin end in said curved groove and wherein, when said wheel-deployment actuating means is actuated, said locking pin and said side rail cooperate so as to allow said wheel-deployment means to shift said wheel-mounting bracket between a deployed-wheel position and a retracted-wheel position.
 4. The wheel unit of claim 3, wherein said second end of said locking pin is slidably movable along said curved groove and lockable respectively in said first locking position at said deployed-position latching end and in said second locking position at said retracted-position latching end.
 5. The wheel unit according to claim 3; wherein said side rail has an actuating end and said wheel-deployment actuating means is a handle that is mounted at said actuating end of said side rail and is grippable.
 6. The wheel unit according to claim 3, wherein said wheel-deployment actuating means is a mechanical means having a first end fixedly attached to said ski and a second end linked to said actuating end of said side rail so as to urge said wheel-deployment means toward said retracted-wheel position.
 7. The wheel unit according to claim 6, wherein said mechanical means includes a biasing spring.
 8. The wheel unit according to claim 3, wherein said wheel-deployment actuating means is an electrical means having an electrical drive means at said first end fixedly attached to said ski and a linkage that extends from said drive means and is linked to a said actuating end of said side rail.
 9. The wheel unit according to claim 3, wherein said wheel-deployment actuating means is a pressurized-fluid system having a cylinder fixedly attached to said ski and a retractable piston that extends from said cylinder and is attached to said actuating end of said side rail so as to move said wheel-deployment means between said deployed-wheel position and said retracted-wheel position.
 10. The wheel unit according to claim 9, wherein said pressurized-fluid system is a hydraulic system.
 11. The wheel unit according to claim 9, wherein said pressurized-fluid system is a pneumatic system.
 12. The wheel unit according to claim 3, wherein said wheel-deployment actuating means is automated and includes a switch mountable in an area of said vehicle that is readily accessible to an operator of said vehicle and that sends a signal to said wheel-deployment actuating means that causes said wheel-deployment means to move between said retracted-wheel position and said deployed-wheel position.
 13. The wheel unit according to claim 1 further comprising a wheel-unit indicator that indicates said deployed position of said wheels, wherein said ski-mounted vehicle has a dashboard and said indicator is mountable on said dashboard and connectable to said wheel unit.
 14. A ski for use with a ski-mounted power vehicle, said ski comprising: an inner bottom ski surface, kingpin-mounting holes for connecting said ski to said ski-mounted power vehicle; ski side walls that extend upward from said inner bottom surface, a wheel unit according to claim 1 mounted on a kingpin that extends through said kingpin-mounting holes.
 15. A wheel unit mountable on a ski of a ski-mounted vehicle, said ski having a gliding surface for traveling over a ground surface and two side walls, a first side wall and a second side wall, that extend upward from said gliding surface and lengthwise along at least a portion of said ski, said wheel unit comprising: a side-wall mounting bar a wheel assembly that includes an eccentrically mounted wheel, a wheel-deployment means having a side rail, a latching mechanism, and a wheel-deployment actuating means between a deployed-wheel position and a retracted-wheel position; wherein said side-wall mounting bar is mountable on an outside of said first side wall of said ski and said wheel-deployment means is mountable on said side-wall mounting bar; and wherein said wheel assembly is mountable on said wheel-deployment means.
 16. The wheel unit according to claim 15, wherein said wheel assembly includes a wheel mounting bracket that includes with cam with a wheel-mounting spindle for mounting said wheel on said bracket, a cam spindle for rotatably mounting said wheel-mounting bracket on said side-wall mounting bar, and a deployment end that attaches shiftably to said side rail.
 17. The wheel unit of claim 16, wherein said latching mechanism includes a locking pin and a curved groove in said side rail, said curved groove having a first latching position and a second latching position; and wherein said locking pin is fixedly attached at a first end to said side-wall mounting bar and is slidably captured at a second end in said curved groove, and wherein said locking pin and said side rail cooperate so as to allow said deployment means to shift said wheel between said deployed-wheel position and said retracted-wheel position.
 18. The wheel unit according to claim 16, wherein said side rail has an actuating end and said wheel-deployment actuating means is a handle that is mounted at said actuating end of said side rail and is grippable.
 19. The wheel unit according to claim 17 further comprising two side-wall mounting bars, wherein said wheel deployment means includes said two side rails and a crossbar, wherein the side-wall mounting bars are mounted to each one of said side walls and a respective one of said two side rails is mounted on each of said side-wall mounting bars such that said side rails are parallel and an imaginary line drawn between said first end of each of said side rails extends perpendicular to said side walls, and wherein said handle is a crossbar has two ends, each end of which is mounted at said actuating end of a respective one of said side rails.
 20. The wheel unit of claim 19, wherein said wheel-deployment actuating means includes a drive means that is mounted on said side-wall mounting bar and an operative end that is linked to said actuating end of said side rail so as to move said wheel-deployment means between said deployed-wheel position and said retracted-wheel position.
 21. The wheel unit according to claim 20, wherein said drive means is a biasing spring. that is fixedly attached to said side-rail mounting bar at one end and to said actuating end of said side rail at another end.
 22. The wheel unit according to claim 21, wherein said drive means is an electrically actuated drive means.
 23. The wheel unit according to claim 22, wherein said drive means is a pressurized-fluid system having a cylinder fixedly attached to said side-wall mounting bar and a retractable piston at said operative end that is attached to said actuating end of said side rail.
 24. The wheel unit according to claim 23, wherein said pressurized-fluid system is a hydraulic system.
 25. The wheel unit according to claim 23, wherein said pressurized-fluid system is a pneumatic system.
 26. The wheel unit according to claim 15, said ski further comprising a carbide-fastening assembly and a carbide fastener, wherein said side-wall mounting bar includes a mounting end adapted to seat over said carbide fastening assembly and a through-bore for receiving said carbide fastener.
 27. The wheel unit according to claim 26, wherein said carbide fastening assembly includes a first fastening post and a second fastening post, and wherein said mounting end of said side-wall mounting bar includes a first mounting end adapted for seating over said first fastening post and a second mounting end adapted for seated over said second mounting post.
 28. A ski-and-wheel unit comprising: a ski having a gliding surface for traveling over a ground surface and two side walls, a first side wall and a second side wall, that extend upward from said gliding surface and lengthwise along at least a portion of said ski; and a wheel unit according to claim 15; wherein one said wheel unit is mounted on a first side wall.
 29. The ski-and-wheel unit of claim 28, wherein one said wheel unit is mounted on said first side wall and one said wheel unit is mounted on said second side wall.
 30. A combination ski-and-wheel unit comprising: a conventional double-scag type ski having two side walls, a first side wall and a second side all, and a carbide-fastener post with a bore hole for receiving a threaded fastener on said first side wall; a wheel unit according to claim 15, wherein said side-wall mounting bar has a bracket end for receiving said carbide-fastener post, said bracket end having a first through-hole, wherein said side-wall mounting bar is mountable on said first side wall such that said bracket end seats over said carbide-fastener post and said first through-hole is located above said bore-hole on said carbide-fastener post.
 31. The combination ski-and-wheel unit of claim 30, wherein said first side wall includes two carbide fastener posts and said side-wall mounting bar has two bracket ends, each of with seats over a respective one of said carbide fastener posts, and wherein said side-wall mounting bar is fastenable to said first side wall by means of a fastener inserted into said first through-hole on said bracket end and into said bore hole on said side wall.
 32. The combination ski-and-wheel unit of claim 30, wherein said side wall mounting bracket has a second through-hole oriented normal to said first side wall for receiving a fastener to fasten said side-wall mounting bar directly to said first side wall.
 33. A combination ski-and-wheel unit comprising: a ski with a mounting block integrated into a construction of said ski; and said wheel unit of claim 15, wherein said side-wall mounting bar is integral with said mounting block and said wheel-mounting bracket is mounted on said mounting block.
 34. The combination ski-and-wheel unit of claim 33, wherein said mounting block includes a cam spindle mounting bore for receiving said cam spindle of said wheel-mounting bracket.
 35. The combination ski-and-wheel unit of claim 34, wherein said locking pin extends from said mounting block.
 36. The combination ski-and-wheel unit of claim 33, wherein said drive means for said actuation means is mounted on said mounting block and said operative end is attached to said actuating end of said side-rail. 